MADISON, Wis. - The Wisconsin Badgers have less than a week left until their first game of the season against Northern Iowa, so it's understandable that they're trying to narrow down position battles. Head coach Bret Bielema already named Danny O'Brien as the starting quarterback, and the Badgers have a good idea of the wide receivers that will populate their two-deep on Saturday.

But it doesn't look like the battle at right guard is going to wrap up until the end of the week. Several players have rotated in and out of the first and second teams at right guard throughout fall camp, and as of Tuesday Zac Matthias and Kyle Costigan are splitting the first team reps evenly.

Matthias and Costigan are listed as co-starters on the depth chart, and offensive line coach Mike Markuson said they're still trying to find the best five linemen on the team.

"We're trying to find our best five, and we're trying to get one of those guys to step out who wants to be that starter," Markuson said Tuesday. "They're both doing a lot of good things, and we still have a couple days before we go and before we decide who we're going to go with."

The battle between Matthias and Costigan presents an interesting choice for the Badgers, who are looking to rebuild an offensive line that lost three starters from last season. Markuson and the Badgers were able to fill the right tackle and left guard jobs relatively easily, but the right guard spot has been tricky to fill.

Matthias, Costigan, Robert Burge, and Dan Voltz have all gotten reps on the right side at some point during the fall, and Dallas Lewallen could be in the mix for the job later in the season as well. But Voltz and Burge have taken a back seat over the last few days, so the Badgers will need to decide soon between power and polish.

Costigan is widely regarded as one of the strongest offensive linemen on the team, and his physicality impressed the coaches after he changed positions during the spring. But the 6-foot-4 redshirt sophomore is still learning the position after moving from the defensive line, and played in just two games last season on defense.

On the other hand, Matthias has a little bit more experience playing the position. Matthias has played in 17 games during his career, and while that's not very many for a redshirt junior, Markuson praised Matthias' technique after practice Tuesday.

"He's really gotten better fundamentally, doing a lot of good things out there," Markuson said. "He's just got to continue to improve and zero in on every assignment and every fundamental technique."

But Matthias is coming off back surgery to repair two herniated disks, which forced him to miss the end of the 2011 season and all of spring camp. Matthias said he's been fully cleared, but back issues can be tricky to deal with. The 6-foot-5 Matthias said it's taken a little time for him to fully trust his back again, but he thinks he can bring the kind of consistency that Markuson and the Badgers are looking for.

"That's what the coaches are looking for right now," Matthias said. "I believe I can be that consistent player."

In the end, that's what it might come down to. The Badgers have prided themselves on good offensive line play over the last few seasons, and the Badgers will probably end up starting whoever demonstrates the most play-by-play consistency. Matthias and Costigan have about four days left to prove to Markuson and the other coaches that they can be trusted with a starting spot, and it seems like it could go either way from here on out.

"I have no problem with either one of them, no matter who we decide to go with," Markuson said.